Objects in this class interpret the column metadata from a message frame containing a OPCODE_RESULT response to a query giving RESULT_ROWS or RESULT_PREPARED.
It provides lookup of column names and type information,
and provides a convenient accessor to the encoding and decoding support functions,
allowing encoding of bytestrings from perl data when executing a prepared statement,
and decoding of bytestrings to perl data when obtaining query results.

Returns a new column metadata object initialised from the given message frame at the given CQL version number.
(Version will default to 1 if not supplied,
but this may become a required parameter in a future version).

Returns a new column metadata object initialised directly from the given column data.
This constructor is intended for use by unit test scripts,
to create metadata directly from mocked connection objects or similar.

An ARRAY reference containing the data about individual columns.
Each row is represented by an ARRAY reference containing four strings; giving the three components of its name,
and the name of its type:

Returns a boolean indicating whether the column metadata (field names and types) is actually defined. Normally this would be true, except if the object is an instance of Protocol::CassandraCQL::Result returned by executing a prepared statement with metadata specifically disabled.